Abstract:
A dive site was selected at Cape Armitage to conduct a marine benthos survey. The water was approximately 25m deep and the bottom was found to be rocky and inhabited by sponges. Other sites were dived to carry out a survey and assess the area for further work. These sites included Pram Point, Turtle Rocks, the reef drop off adjacent to McMurdo Station and the reverse osmosis hole at Scott Base. ... To survey the marine benthos, two 10m x 10m squares were marked on the sea floor. Within each site, 6 random 1square meter quadrats were surveyed. All organisms within each quadrat were counted and measured. To survey larger, less abundant species, five strip transects were monitored within each site. Each transect was 1m x 10m in area and all large invertebrate species were counted and measured. Their positions on the transect was plotted to allow a future survey aimed at assessing the longevity of large sponges. Sediment spicule mat depth and consistency was also recorded. Sediment type and depth was measured. Three replicate sediment samples were taken to characterize the substrate and rates of sedimentation were determined by installing sediment traps. The site was resurveyed and photographed a year later, with the identity and number of all the species found within each quadrat recorded. Each species sizes were re-measured. Fish counts were also made within both sites. Three 10m x 2m corridors were surveyed within each site and all fish were counted and identified. During both seasons, samples of each species were collected for biochemical investigations. In the first season, 35 benthic species were collected for bioassay of antiviral/antitumour activity. Most of these were benthic encrusting invertebrates. In the second season, 150g of each species found on the reef was collected to test for heterogeneity in each species biochemistry. A 50g sample of all but the rarest species was taken. A small portion was used as a voucher specimen and the remainder frozen. Using this method, little mortality was induced as the basal portion together with at least two thirds of erect portions of each individual was left intact. (Most benthic invertebrates heal quickly and the excised tissue is rapidly replaced). Each species was photographed in situ and again in the laboratory. Colour, texture, consistency, etc was recorded immediately and notes were taken relating to the specimen's ecology and physiology.